


Bucky Barnes Thinks Extremis Is Hot

by JacarandaBanyan



Series: Tony Stark Bingo [6]
Category: Marvel, The Avengers (Marvel Movies), The Avengers (Marvel) - All Media Types, The Avengers - Ambiguous Fandom
Genre: Breathplay, Cock Warming, Consensual Kink, Consensual Loss of Bodily Autonomy, Dom Tony Stark, Established Relationship, Explicit Sex and Fade-To-Black Cuddling, Explicit Sexual Content, Extremis, Extremis Tony Stark, Lab Sex, M/M, Prompt Fill, Sub Bucky Barnes, Subspace, Tony Stark Bingo 2018, Tony Stark Does What He Wants, Tony doesn't even know what lab safety is
Language: English
Status: Completed
Published: 2018-10-14
Updated: 2018-10-14
Packaged: 2019-08-01 21:16:05
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,590
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16291955
Author URL: https://archiveofourown.org/users/JacarandaBanyan/pseuds/JacarandaBanyan
Summary: It starts after Bucky and Tony have finally crossed the line between hanging out all the time and dating, but before they’ve really drawn much attention to it. Bucky still hadn’t broached the topic of orders and how a part of him still wanted to follow them. He didn’t know how to bring it up without making it sound like he was still Hydra’s plaything, but the second he heard Tony say the word ‘hack’ during one of his playing-with-the-arm sessions he knew it was a good idea. Possibly his best idea since dating Tony.What if Tony hacked his arm?





	Bucky Barnes Thinks Extremis Is Hot

**Author's Note:**

> Tony Stark Bingo Square Filled: R2: Kink: Breathplay
> 
> I've had a lot of ideas about hacking Bucky's arm lately.

It starts after Bucky and Tony have finally crossed the line between hanging out all the time and dating, but before they’ve really drawn much attention to it. Bucky still hadn’t broached the topic of orders and how a part of him still wanted to follow them. He didn’t know how to bring it up without making it sound like he was still Hydra’s plaything, but the second he heard Tony say the word ‘hack’ during one of his playing-with-the-arm sessions he knew it was a good idea. Possibly his best idea since dating Tony. 

At first they called it maintenance, but eventually even Tony had to bite the bullet. The thing worked perfectly. He was really just playing at this point. Which is fine by Bucky; it soothed that desire to submit inside him to just sit with his boyfriend and give him a piece of his body to tinker with. 

Tony likes to talk about whatever he’s been thinking about in the STEM world while his fingers dance through the wires of the arm like he’s weaving them into something elaborate and gorgeous, and Bucky is happy to sit back and listen. Today’s topic is cybersecurity and the importance of making sure important information is secure and how more people should be working on it and how the Board had the  _ gall _ to try and stop him from hiring specialists in that field so they wouldn’t have to pay them specialist salaries. 

He’s in the middle of outlining possible nightmare scenarios when inspiration hits Bucky so hard he almost jerks. 

_ What if Tony hacked his arm? _

He reflexively pushes the thought away, but it latches onto the cracks and crevices of his mind and holds firm. His boyfriend certainly had the ability to do it. Even without the aid of Extremis, burning just under his skin and behind his eyes like little electric-blue flames, Tony worked on his arm all the time. He claimed to know the inner workings of Bucky’s hand better than the back of his  _ own _ hand. If there was a way to break in and gain control, Tony would know it. 

Would Tony go for it, though? He always went to such great pains to make it clear that he respected Bucky’s autonomy. He might ask Bucky to  _ explain, _ and then no matter how carefully he chose his words Tony would still come away thinking that he saw him as some of twisted version of a handler, and that wasn’t true at all. He might reject the idea outright on principle. Hell, he might not be comfortable with the very idea, not with a constant reminder in his own chest of the horrors of non-consensual body modification. 

But maybe he  _ would _ go for it, if Bucky could find the right way to ask.

He licks his lips, then hums gently to get Tony’s attention. Extremis-bright eyes flicker up to look at him through those lashes and  _ oh _ that’s good. Steve has confided in him on multiple occasions that it sets him just a little bit on edge whenever Tony uses the virus’s powers around him. Each time Bucky knew Steve was trying to bait him, though in the nicest way possible. Like maybe if the paragon of all that was good and wholesome admitted to thinking it makes Tony look just this side of human, then Bucky would feel that he could admit it too. 

He’s pretty sure Steve will come around. He’s got too good of an artist’s eye to not learn to appreciate it sooner or later. Besides, he’s probably still miffed that Tony used his relatively new powers to hack project a picture of an eagle with Steve’s face photoshopped on top of it on the walls last week when they got into a fight over something dumb. He’ll get over it.

“Did you say something, love?” Tony asks. 

He refocuses on the conversation at hand. He loves Steve like a brother, but he doesn’t need to be thinking about him when he’s trying to score some kinky sex with his boyfriend.

“Yeah. You just gave me a fabulous idea.”

Tony raised an eyebrow. “Let’s hear it then.”

Here goes nothing. “What if your used Extremis to hack my arm?”

Tony rears back from him like a startled snake preparing to strike. The glow in his eyes fades a bit as he disconnects from the who-knows-how-many programs he’d been hooked up to so he could focus on this particular conversation. As much as he appreciates the glowing eyes, having Tony’s full attention is just as nice.

“And just so we’re on the same page, that’s a  _ good _ idea?” He asks.

“Best one I’ve had since I started giving you fake coffee when you hit hour 16 in the lab without food or sleep breaks.” He says innocently. 

“Excuse me, what do you mean  _ fake coffee? _ ” The look of horrified betrayal on Tony’s face is really something. Maybe he can sweet-talk Jarvis into giving him a copy from the security footage later.

“I’ve started crushing melatonin tablets to help you sleep and putting them in warm chocolate milk. The brown color makes you think it’s coffee.”

Tony gasped and help a hand up to his heart dramatically.

“How could you betray me like this? I trust you to give me coffee that hasn’t been poisoned or otherwise Dum-E-fied, and this is how you reward my trust? By  _ deceiving _ me? Well, it won’t work again! The next time you hand me something that doesn’t contain enough caffeine to give a cow a heart attack, I’ll be ready!”

He’s waving his hands dramatically and dancing around Bucky’s chair. Holograms and half-completed projects move to avoid getting knocked over, and Bucky swears he can hear the sigh in Jarvis’s voice when he says “Sir, please be careful.”

“It’s so cute how you think you’ll even notice.” Bucky grins. “Did you miss the part where I gave you heated up chocolate milk with some sleepy-time boosters in it and you legitimately thought it was coffee?”

Tony grumbles and gets back to work on whatever feature it was that he wanted to add to the arm.

“And it wouldn’t bother you, for me to take control of a literal part of your body?”

“I think I’d like it if you took control of me.”

Tony snorts, but he’s sizing up the arm and the glint in his eyes is different from the engineering glint that was there a second ago, so Bucky knows he’ll say yes.

* * *

Bucky feels his hand ride to his throat without his permission and a wave of warmth washes over him. He looks up at Tony, who’s still sitting on the end of the bed and smiling that excited smile. It just rests there, not constricting anything at all, but keeping the promise of more to come ever-present against his quickening pulse.

“Still good?” Tony asks.

“Yeah,” Bucky grins. “Do what you want.”

Extremis glowed ember-bright behind his eyes, and Bucky’s fingers began stretching and curling around his neck, though still not pressing down. His erection is growing in his sweatpants and he can’t even find a spare scrap of attention to give it. Everything is focused on the arm he can no longer control and on Tony, whose smile is getting warmer and warmer as the temperature of the lab rises. 

“Getting a little hot under the collar there, doll?” He asks. He can feel his own voice against the metal hand; the sensory feedback Tony has left untouched for now. 

Tony laughs darkly and Bucky feels his hand constrict for just a fraction of a second, barely more than a flutter. 

“What can I say, Snowflake, I’ve got a tech boner you can see from space and you’ve got really nice muscles. You could probably bench press me for hours without even breaking a sweat.” He smiles wider, like a shark. “And you’re still going to let me push you around, aren’t you?”

Bucky smiles and goes limp against the bed. 

“Sure. Go ahead.”

Tony leans over and kisses his forehead, sweet and soft and chaste, then straightens up and makes like he’s going somewhere. Bucky’s forehead wrinkles in confusion, but he doesn’t voice his questions yet.

“Good, because Dum-E’s managed to loosen like twenty bolts in the past month, and I want your help fixing them. That asshole Clint taught him how to dab, and now he does it because he thinks it’s new and cool, when in reality it’s just a recipe for knocking things over and messing up his wires. It’s the jerkiness of the movement that does it, you know. He’s not supposed to move like that.”

The arm flexes against his neck, then slides down his side to his thigh. The metal fingers dig into the flesh there, and the arm pulls him upright. Once he’s sitting, the arm extends itself elegantly to Tony, who takes it with theatrical bowing, like an old-timey gentleman accepting a court lady’s offered arm. He even leans down to kiss the metal knuckles. 

Bucky laughs and goes to play-shove Tony, but the arm doesn’t move so much as an inch. His dick pulses against the waistband of his sweats. 

“God that’s hot, doll.”

Tony smiles. His whole face turns inviting and soft, and he wants to gently reach out and stroke it but his arm is listening to Tony’s commands instead of his and his other arm is on the wrong side and it would be awkward if he tried to reach. He settles for blowing him an exaggerated kiss instead. Tony giggles and pulls him into the elevator. 

Once they’re inside the arm finally drops back to his side, only to reach over to the wall and  _ push _ so that the rest of him half-stumbles half-flies into the corner. His back slams against the wall. Tony follows at a more leisurely pace. He crowds Bucky into the corner like a languid cat cornering a mouse. He’s smaller than Bucky, but Bucky’s want-pliant body doesn’t even know how to do anything but relax and submit. 

Bucky whines high in his throat when Tony presses up against him, creating an unbroken line of contact from their knees to their chests. Heat radiates through Tony’s clothes and warms his grasping hands like hot cocoa. He pulls Tony a little closer with his flesh hand and rubs lightly against his thigh. Tony responds with an enthusiastic kiss. 

His metal hand snakes under Tony’s shirt and pulls him a little bit closer. Tony waggles his eyebrows at him, then cheekily thrusts once against him. He laughs, and presses a kiss to Tony’s cheek. 

“You’re ridiculous.”

“So are you. Now be a good boyfriend and get that hand down my pants.”

Bucky buries his face in Tony’s shoulder, but his metal arm obediently slides down Tony’s back and slips inside his pants. His palm squeezes Tony’s ass lightly, appreciatively, and he moans into Tony’s overheated skin. 

“Thanks doll. Your ass feels phenomenal.”

Tony laughs, and the vibrations spill across his throat into the skin of his shoulder and onto Bucky’s cheek, where they shift his face into an even wider smile. 

“My pleasure.”

Bucky’s attention is all on the arm and what it will do next. Sometimes twitches and pulls in his shoulder muscles can give him a hint, but all he can really do is guess. 

Then suddenly the elevator dings and his arm slips out and to his side again and Tony backs up so Bucky can follow him into the workshop. 

“Dum-E,” he calls, “come on out. Daddy’s here to fix you up.”

A cascade of beeps and whirls sounds off from the charging stations in the back, and Dum-E rolls over to them. 

“Yeah, yeah, complain all you want, you’re the one that got yourself into this mess. I told you to knock it off but did you listen to me? Of course not, why would you ever do a thing like that?”

And just like that the immediacy of the elevator is gone and Bucky’s arousal simmers back down to more manageable levels. 

He follows Tony over to where Dum-E is waiting for them. The arm swings deceptively lazily at his side, like it hadn’t done anything at all unusual today. 

Tony leads him over to a workbench, where he gestures for Bucky to sit. At least, he thought that was what he wanted, but when Bucky does sit, he frowns and shakes his head.

“Not there, silly, on the floor under the table. Aren’t submissive-types like you supposed to kneel?”

Bucky’s arousal is back to a roaring flame again, and he nods enthusiastically as he sinks to the floor and crawls to the protected spot Tony had pointed to. 

“Absolutely, my mistake.”

Tony smiles. “Well, it’s such an easy thing to fix, so I’ll let you off the hook this time.” 

He sits down in front of where Bucky’s kneeling and starts undoing his fly. Bucky’s mouth starts to water, and if his cock was any harder Tony could use it as some sort of engineering tool. A screwdriver, maybe, or a crowbar. Tony carefully pulls his cock out of his pants, then taps his lips. Bucky opens them obediently, and Tony feeds his half-hard cock into his mouth.

“There we go. I’m just going to do this job real fast, and then we’ll get to something a little more fun for you, okay? This might make breathing a bit more difficult, so tap my thigh with the arm you still have if you need some air.”

Bucky nods shallowly. 

Tony shivers, then grabs a screwdriver. 

Time turns to taffy as Tony works. Every once in a while Bucky’s arm moves under Tony’s control to grab a bolt or tool and hand it up to Tony, who pats him appreciatively on the head each time. Under his chin, Tony’s thighs flex and strain in time with his upper body, and sometimes his skin heats up just a little too much for a regular human as Tony let’s off some of Extremis’s extra heat. 

And Bucky just sinks right into Tony’s control. 

* * *

Bucky’s pretty sure that Tony finished with Dum-E long ago. For one thing, Dum-E’s on the other side of the lab, and Tony’s saying something to Jarvis about how lab safety protocols don’t apply to superheroes. He doesn’t mind. Tony’s in charge, and if Tony wants to be productive then Bucky’s not going to be the one who gets in his way.

He lets his eyes drift upward to he can get a good look at what Tony’s working on now. The sight that meets him is enough to take his breath away all over again. His cock pulses to life in his awareness, and he has to tamp it back down so he doesn’t get distracted from staying still and obedient for Tony.

His boyfriend’s hands are glowing red-hot and are just as bright as his eyes in the elevator. When he looks away, he’s sure the light burning from those hands will leave afterimages clouding his sight. If one of those hands reached down to cup Bucky’s face, it would brand him with Tony’s handprint. His dick, ever the unrealistic thinker, says that that’s a fabulous idea. 

There’s some sort of metal in his hands, metal that’s gone soft and malleable. Tony’s  _ welding with his hands  _ and how could anyone ever even pretend that Extremis wasn’t every kind of hot?

As he watches, Tony achieves whatever it was that he wanted and holds the metal shape up for inspection. Not a single spark has flown. Tony’s controlling the metal with his hands just as surely as he’s controlling Bucky’s arm with his mind.

Tony glances down at him and smiles, and  _ oh god he’s breathing fire. _ Golden flames flicker between his teeth like a hundred curious lizard tongues. The light of the fire makes his teeth stand out as dark, sinister silhouettes. Bucky tries to make this predator mesh with the soft, sleepy man he brought fake coffee to just a few days ago but his head is so fuzzy that all he can think is  _ now all that fire inside you is on the outside where everyone can see it. _

Then he sees his metal arm reach up and hold something in place so Tony can weld the metal to the end of it, and sinks like a stone right back into that taffy-time headspace. 

* * *

At long last, Tony sets aside his tools and dismisses the holoscreens. He reaches down and brushes his fingers through Bucky’s hair with normal human-temperature fingers.

“All done. Now, let’s get that hand back around your neck, okay?” Tony’s eyes sparkle with laughter as he sing-songs that last ‘okay?’ like Bucky has any say in the matter whatsoever. “I think I know how to make this even better.”

Bucky tries to breathe in around Tony’s cock but it’s hard when he’s pulse is skipping like a perfectly flung stone over flat water and all the heat in his face just concentrated in his blushing cheeks. His face is probably hot enough to compare to Tony’s Extremis-warm skin at this point. 

The arm slides up his slowly side, stopping now and again to pinch him or squeeze a muscle in his side. His skin pebbles up like a riverbed under the trickles of sweat mapping out lines of wetness on his chest and back. It brushes over his nipple, then gyres back around like an hunting hawk and pinches it. Finally, it reaches his throat and settles palm-down around his flesh like a collar.

“Oh, Bucky, you look so hot like that.” Tony praises him. His hands keep stroking through his hair, but there’s a little more pressure there now, a promise of fun to come. “Take a deep breath, now. You’ll want it in a minute or so.”

Bucky inhales and inhales until his lungs won’t expand anymore and his chest feels like a fully blown up balloon that, were it not for the weight of Tony’s cock on his tongue, would have lifted him off the ground and floated him aimlessly around the Tower. His eyes flick up to meet Tony’s, and he nods as best he can with his mouth skewered the way it is. 

Suddenly the metal fingers tighten on the sides of his throat, just a little bit, like a pincer attack. The palm is still relaxed (or as relaxed as metal can ever be) against the front. A little bit of his air leaks out as his throat closes, but he stays still and as loose as possible. 

The arm gives a few more careful, exploratory squeezes, then shifts so that the palm is against the nape of his neck rather than the front. It strokes up and down, looking for the perfect spot. Above him, Tony’s eyes are focused and bright. 

The fingers compress again, stronger this time. He might end up with some bruises when this is all over. 

And then finally, finally Tony pushed forward into his mouth in one long, luxurious slide. His head bumped lightly against the back of his mouth, then slipped down into his throat, which was much tighter now than it would have been without the fingers compressing it. Tony moans above him and keeps sliding until Bucky’s face is pressed up against his pubic hair and he wouldn’t be able to breathe even if Tony released his throat. 

For a second Tony just holds the arm still, face slack with pleasure and making little aborted thrusts like little pulses against Bucky’s tongue. Then the glow behind his eyes strengthens and the arm starts moving back and forth, making Bucky’s throat slip over his cock like he’s just a sleeve to thrust into and get off in. Bucky moans as best as he can. Every so often he slackens the arm enough that Bucky can suck some air around his cock, but for the most part he’s living off the stale, used up air in his lungs and it’s making his head a little cloudy, or maybe that’s just the domination? Has his head ever felt like this when Tony gave him orders in the past? It’s difficult to say, and focusing on anything but Tony is so hard. 

This is exactly what he wanted when he had this idea. Tony using Bucky’s own arm to work his throat like a fleshlite over his cock, what better picture could there possible be? His orgasm sneaks up on him, and all of a sudden he’s coming on Tony’s cock, whining and basking in all the excess heat leaking from Tony’s skin. Tony doesn’t even pause his squeezing. 

Bucky moans, and goes boneless on his thighs.

He’s not really sure how much later Tony comes, just that at one point he starts thrusting with a bit more purpose, and not much later he’s coming down his throat and the contented, controlled feeling gets impossibly stronger. 

Tony pulls out of his mouth carefully and wipes a little smear of spit off his lips for him.

“You did so good honey, that was amazing. You feeling thirsty, or are you ready for bed?”

Bucky searches through his slow, foggy mind for an answer, but Tony’s patient and waits for him to think. Tony’s the best.

“Bed,” he says at last. “Wanna cuddle.”

Tony smiles, and it’s soft and cute and completely different from the fire-breathing dragon smile. “Sounds good to me.”


End file.
